1. Field of the Invention
The present invention relates to an access device for a data-holding body, such as a reader/writer module for IC cards, and to electronic equipment incorporating the access device. More specifically, the invention relates to a reader/writer module for IC cards having a reduced thickness and to electronic equipment incorporating the reader/writer module for IC cards. The equipment is not increased in the size as a result of using the IC card reader/writer.
2. Description of the Related Art
In recent years, there have been widely employed user authentication and electronic money using cards such as credit cards and services such as point cards. As such cards, there have heretofore been used magnetic cards having a magnetic stripe. However, the data recorded in the magnetic stripe can be erased by the application of an intense magnetic field and are, further, liable to be used without authorization by being read by a third person by using a magnetic reader.
There have further been widely used IC cards incorporating an IC therein and exposing terminals for connection to the input/output terminals of the IC on the surface of the cards to substitute for the magnetic cards. By using the card incorporating the IC, however, the data recorded in the IC must be read out by using a reader/writer of the contact type making it necessary to insert the IC card in the reader/writer and, hence, requiring a reading operation.
Therefore, it has been urged to provide a non-contact type IC card that need not be brought into contact with the reader/writer to substitute for the conventional magnetic cards and the IC cards of the contact type. The IC cards of the non-contact type are now available as commuter's tickets and prepaid tickets for railways and buses, and as prepaid electronic money which can be used at specified shops.
The non-contact type IC card contains an IC chip, a peripheral circuitry and a loop antenna, and works upon trapping very weak electromagnetic waves, from the reader/writer which is also equipped with an antenna, and sends the data recorded in the IC chip back to the reader/writer through the antenna. To further spread the use of the non-contact type IC cards, attempts have been made to incorporate the reader/writer for the non-contact type IC card in various electronic equipment such as a personal computer.
The non-contact type IC card has no connection terminal, and it is possible that a good communication cannot be accomplished depending upon the positional relationship between IC card and the reader/writer. Some conventional reader/writer modules use large antenna enabling the users to accomplish favorable communication without the need of giving much attention to the positioning between the IC card and the reader/writer module. In other cases, further, the electromagnetic output power is increased to accomplish good communication. In a reader/writer using a small antenna and suppressing the output power, further, attempts have been made to provide a rack for placing the IC card enabling the user to correctly position the IC card as employed in some convenience stores.
To accomplish favorable communication by using a loop antenna employed by the non-contact type IC cards, however, attention must be given not to arrange a metallic member that blocks the transmission/reception of electromagnetic waves on the upper and lower sides, on the right and left sides, or on the back of the antenna of the reader/writer. When it is necessary to arrange a metallic member just under the antenna of the reader/writer, a magnetic sheet must be inserted between the antenna and the metallic member.
Japanese Unexamined Patent Publication (Kokai) No. 2002-298095 discloses an example of sticking a flexible sheet-like magnetic body under the antenna coil or onto the back of the casing of the reader/writer for communicating the data with the IC card.
In the conventional reader/writer module for IC cards, the loop antenna is mounted on the substrate by means such as printing or adhesion, and a circuit component including the IC chip having memory for recording data is mounted by the side of the loop antenna. When it is necessary to arrange the reader/writer on a portion where a metallic member is arranged just under the loop antenna of the reader/writer, a magnetic sheet is stuck to the back surface of the substrate corresponding to the loop antenna to prevent the effect of the metallic member.
When it is attempted to employ a large antenna or to increase the output power, however, it becomes difficult to keep the size of the device small. According to the method of providing the housing with a rack for positioning the card, the rack could become an obstacle when the reader/writer is incorporated in a place on where the user usually puts his hand, such as a palm rest portion or the like of a notebook personal computer. When the reader/writer is incorporated in a small electronic equipment, further, it may become necessary to provide the magnetic sheet on the back surface of the antenna to suppress the interference with the metallic member causing an increase in the thickness of the reader/writer module and making it difficult to incorporate it in small electronic equipment.